The test tube spinner is another open source laboratory equipment design. The design was created by Keith Yeager and a demo model was built at Cooper Union. The device is made from .25” laser cut ABS, a few basic electronic components, and a gear motor for rotation. The spinning plate can hold many test tubes but only three are shown on the plate in the demo unit due to a lack of ABS to make more clips for the plate.

Wire the power supply, motor, switch, and optional speed control according to the circuit diagram below.

The motor gets mounted to the front piece using screws.
Then mount the switch and tuck away the wires. A potentiometer for adjusting the speed pokes through a hole in the top.

The rest of the spinner snaps together to form the enclosure and gets placed on the base. Unless the snap fit is very strong, some cement may be needed to hold the spinner together.

Base

Main box

As seen below, the spinning plate and the motor must be joined in a way that can transmit a fair amount of torque. A D-shaped piece of plastic was made that uses a set screw to attach to the motor shaft and the spinning plate slides over. This was then glued together.

The one limitation of the spinner is that the spinning plate is large enough that the unit must be used on the edge of a table. Also this unit was built with only three clips for demonstration purposes.